1. Field of the Invention
The present invention relates to a charged particle beam drawing equipment for use in a lithography process, a method of adjusting an aperture mask in the drawing equipment, and a method of manufacturing a semiconductor device.
2. Description of the Related Art
With a finer and highly denser integrated circuit, there has been a demand for a charged particle beam emitting apparatus for emitting a charged particle beam or a focused ion beam which is capable of making stable operation as a semiconductor device mass-production device, achieving high throughput, and achieving finer processing capability.
In recent years, a technique for mass-production has been developed for a charged particle beam drawing equipment as well. Such a technique includes a variable shaping beam (VSB) system for producing rectangular and triangular beams of arbitrary sizes by using a plurality of apertures and a cell projection exposure system having a repetition cell (CP) mounted in advance on an aperture mask. In these systems, the position and rotation precision of the aperture are reflected on drawing precision. Thus, it is important that the aperture mask is adjusted with high precision. As the adjustment time becomes longer, equipment operability is lowered. However, a shorter adjustment time is desired.
One of the conventional aperture mask adjusting methods includes a knife edge system using an edge of an opening portion of each aperture mask (Japanese Patent No. 3102632). In this system, it is mandatory that control means for scanning a charged particle beam is precisely adjusted. Thus, a time interval required for adjusting a rotation angle of an aperture mask becomes longer by a time interval required for adjusting the control means with high precision. In addition, it is necessary that the edge of the opening portion of each aperture mask is precisely formed. However, it is difficult to form the edge of the opening portion of each aperture mask with high precision. Therefore, the conventional aperture mask adjusting method cannot be simply used because it requires a long time interval or a precisely formed edge.